Steerable guide catheter

ABSTRACT

A flexible guide tube having a deflectable distal end is disclosed with at least first and second tensioning lines coupled to a deflectable distal end of the flexible guide tube. The first tensioning line is configured to deflect the distal end of the flexible guide tube in a first direction and the second tensioning line is configured to deflect the distal end of the flexible guide tube in a second direction that is opposite the first direction. A handle is coupled to flexible tube, the handle having a medial portion with a longitudinal axis substantially parallel with at least a portion of the flexible guide tube, a first actuator disposed proximal the medial section, and a second actuator disposed distal the medial section.

FIELD OF THE INVENTION

The present technology relates generally to medical devices, systems,and associated methods. More particularly, the present technologyrelates to devices, methods, and systems for steering a flexible guidecatheter or introducer, including, but not limited to, those used inprocedures related to treatment of the heart.

BACKGROUND

Many medical procedures require the introduction of specialized medicaldevices, such as catheters, dilators, and needles, to a target area ofthe body, such as into the area surrounding the heart. Catheters andaccess sheaths or introducers have been used for such medicalprocedures. It is necessary for introducers and catheters to exhibit adegree of flexibility to maneuver through the vasculature of a patientto perform medical procedures. In addition, various configurations ofintroducers are necessary for the treatment of different conditions orbody areas. Handles are often affixed to such devices to enable aphysician or practitioner to manipulate the catheter as it is insertedand advanced into the patient. Different handles are required, however,to accommodate the many different preferences of medical practitioners.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a steerable guide catheter in accordancewith one aspect of the technology;

FIG. 2A is a cross-sectional view of a guide tube in accordance with oneaspect of the technology;

FIG. 2B is a cross-sectional view of a guide tube in accordance with oneaspect of the technology;

FIG. 3 is a side view of a portion of a steerable guide catheter with aportion of the housing removed in accordance with one aspect of thetechnology;

FIG. 4 is back perspective view of a steerable guide catheter with aportion of the housing removed in accordance with one aspect of thetechnology; and

FIG. 5 is a back perspective view of a steerable guide catheter with aportion of the housing and valve removed in accordance with one aspectof the technology.

DESCRIPTION OF EMBODIMENTS

Although the following detailed description contains many specifics forthe purpose of illustration, a person of ordinary skill in the art willappreciate that many variations and alterations to the following detailscan be made and are considered to be included herein. Accordingly, thefollowing embodiments are set forth without any loss of generality to,and without imposing limitations upon, any claims set forth. It is alsoto be understood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting. Unless defined otherwise, all technical and scientific termsused herein have the same meaning as commonly understood by one ofordinary skill in the art to which this disclosure belongs.

As used in this written description, the singular forms “a,” “an” and“the” include express support for plural referents unless the contextclearly dictates otherwise. Thus, for example, reference to “a layer”includes a plurality of such layers.

In this disclosure, “comprises,” “comprising,” “containing” and “having”and the like can have the meaning ascribed to them in U.S. Patent lawand can mean “includes,” “including,” and the like, and are generallyinterpreted to be open ended terms. The terms “consisting of” or“consists of” are closed terms, and include only the components,structures, steps, or the like specifically listed in conjunction withsuch terms, as well as that which is in accordance with U.S. Patent law.“Consisting essentially of” or “consists essentially of” have themeaning generally ascribed to them by U.S. Patent law. In particular,such terms are generally closed terms, with the exception of allowinginclusion of additional items, materials, components, steps, orelements, that do not materially affect the basic and novelcharacteristics or function of the item(s) used in connection therewith.For example, trace elements present in a composition, but not affectingthe compositions nature or characteristics would be permissible ifpresent under the “consisting essentially of” language, even though notexpressly recited in a list of items following such terminology. Whenusing an open ended term, like “comprising” or “including,” in thiswritten description, it is understood that direct support should beafforded also to “consisting essentially of” language as well as“consisting of” language as if stated explicitly and vice versa.

The terms “first,” “second,” “third,” “fourth,” and the like in thedescription and in the claims, if any, are used for distinguishingbetween similar elements and not necessarily for describing a particularsequential or chronological order. It is to be understood that any termsso used are interchangeable under appropriate circumstances such thatthe embodiments described herein are, for example, capable of operationin sequences other than those illustrated or otherwise described herein.Similarly, if a method is described herein as comprising a series ofsteps, the order of such steps as presented herein is not necessarilythe only order in which such steps may be performed, and certain of thestated steps may possibly be omitted and/or certain other steps notdescribed herein may possibly be added to the method.

The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,”“under,” and the like in the description and in the claims, if any, areused for descriptive purposes and not necessarily for describingpermanent relative positions. It is to be understood that the terms soused are interchangeable under appropriate circumstances such that theembodiments described herein are, for example, capable of operation inother orientations than those illustrated or otherwise described herein.The term “coupled,” as used herein, is defined as directly or indirectlyconnected in an electrical or nonelectrical manner. Objects describedherein as being “adjacent to” each other may be in physical contact witheach other, in close proximity to each other, or in the same generalregion or area as each other, as appropriate for the context in whichthe phrase is used. Occurrences of the phrase “in one embodiment,” or“in one aspect,” herein do not necessarily all refer to the sameembodiment or aspect.

As used herein, the term “substantially” refers to the complete ornearly complete extent or degree of an action, characteristic, property,state, structure, item, or result. For example, an object that is“substantially” enclosed would mean that the object is either completelyenclosed or nearly completely enclosed. The exact allowable degree ofdeviation from absolute completeness may in some cases depend on thespecific context. However, generally speaking the nearness of completionwill be so as to have the same overall result as if absolute and totalcompletion were obtained. The use of “substantially” is equallyapplicable when used in a negative connotation to refer to the completeor near complete lack of an action, characteristic, property, state,structure, item, or result. For example, a composition that is“substantially free of” particles would either completely lackparticles, or so nearly completely lack particles that the effect wouldbe the same as if it completely lacked particles. In other words, acomposition that is “substantially free of” an ingredient or element maystill actually contain such item as long as there is no measurableeffect thereof.

As used herein, the term “about” is used to provide flexibility to anumerical range endpoint by providing that a given value may be “alittle above” or “a little below” the endpoint. Unless otherwise stated,use of the term “about” in accordance with a specific number ornumerical range should also be understood to provide support for suchnumerical terms or range without the term “about”. For example, for thesake of convenience and brevity, a numerical range of “about 50angstroms to about 80 angstroms” should also be understood to providesupport for the range of “50 angstroms to 80 angstroms.”

As used herein, the term “tensioning line” is used to describe anynumber of devices or mechanisms by which a force is applied to a portionof a guide tube. The force may be applied as a result of a “pulling”force exerted on a connector or wire extending from the distal end ofthe guide tube to a proximal end of the guide tube, a “pushing” force,the result of deformation of a connector or wire in the distal end ofthe guide tube due to a change in temperature, etc. or any other meanswhereby a flexible element disposed within the distal end of the guidetube exerts a flexing or tensioning force on portion of the guide tube.

The term “guide catheter” is used herein to describe any number ofguiding elements used to place a “treating catheter” or “treatinginstrument” into a patient. In one aspect, the guide catheter is removedbefore treatment of the patient begins and the treating catheter remainsin the patient. The guide catheter may be a solid guide wire over whichthe treating catheter is placed or a hollow guide tube through which thetreating catheter is placed. In one aspect, after placement of thetreating instrument, the guide catheter is removed from the patient. Inanother aspect, however, the guide catheter remains in place while atreating instrument is advanced to a location within the patient andremains in place while one or more treating instruments (e.g., ablationtool, suturing tool, etc.) are employed by a clinician. At thetermination of the procedure, the treating instruments and guidecatheter are removed from the patient. While specific mention is madeherein to use of the technology in the vasculature of the patient, it isunderstood that the technology may be employed to advance a guidecatheter into any portion of the body.

As used herein, a plurality of items, structural elements, compositionalelements, and/or materials may be presented in a common list forconvenience. However, these lists should be construed as though eachmember of the list is individually identified as a separate and uniquemember. Thus, no individual member of such list should be construed as ade facto equivalent of any other member of the same list solely based ontheir presentation in a common group without indications to thecontrary.

Concentrations, amounts, and other numerical data may be expressed orpresented herein in a range format. It is to be understood that such arange format is used merely for convenience and brevity and thus shouldbe interpreted flexibly to include not only the numerical valuesexplicitly recited as the limits of the range, but also to include allthe individual numerical values or sub-ranges encompassed within thatrange as if each numerical value and sub-range is explicitly recited. Asan illustration, a numerical range of “about 1 to about 5” should beinterpreted to include not only the explicitly recited values of about 1to about 5, but also include individual values and sub-ranges within theindicated range. Thus, included in this numerical range are individualvalues such as 2, 3, and 4 and sub-ranges such as from 1-3, from 2-4,and from 3-5, etc., as well as 1, 2, 3, 4, and 5, individually.

This same principle applies to ranges reciting only one numerical valueas a minimum or a maximum. Furthermore, such an interpretation shouldapply regardless of the breadth of the range or the characteristicsbeing described.

Reference throughout this specification to “an example” means that aparticular feature, structure, or characteristic described in connectionwith the example is included in at least one embodiment. Thus,appearances of the phrases “in an example” in various places throughoutthis specification are not necessarily all referring to the sameembodiment.

Reference in this specification may be made to devices, structures,systems, or methods that provide “improved” performance. It is to beunderstood that unless otherwise stated, such “improvement” is a measureof a benefit obtained based on a comparison to devices, structures,systems or methods in the prior art. Furthermore, it is to be understoodthat the degree of improved performance may vary between disclosedembodiments and that no equality or consistency in the amount, degree,or realization of improved performance is to be assumed as universallyapplicable.

Example Embodiments

An initial overview of technology embodiments is provided below andspecific technology embodiments are then described in further detail.This initial summary is intended to aid readers in understanding thetechnology more quickly, but is not intended to identify key oressential features of the technology, nor is it intended to limit thescope of the claimed subject matter.

Broadly speaking, aspects of the current technology operate to improve amedical practitioner's ability to steer a flexible guide catheter withina cavity of a patient. A cavity may include, but is not limited to, avessel, a canal, a tissue opening, or other opening within the body ofthe patient. In order advance a catheter into the cavity of a patient,including, but not limited to the vascular system, a catheter must besubstantially stiff to move through the vasculature of a patient. Thatis, while gripping the catheter on its proximal end, the distal end musthave sufficient stiffness to not to kink while pushing the proximal endof the catheter when the distal end encounters resistance. A stiffcatheter, however, creates patient discomfort and potentially dangeroussituations when trying to advance a catheter through circuitous portionsof the vasculature. A stiff but steerable guide can be used to navigatea vascular pathway after which a more flexible, comfortable treatingcatheter can be placed over or through the steerable guide tube. In oneaspect, the flexible guide tube has a deflectable distal end with twotensioning lines disposed on opposing sides of the deflectable distalend. The first tensioning line is configured to deflect the distal endof the flexible guide tube in a first direction and the secondtensioning line is configured to deflect the distal end of the flexibleguide tube in a second direction that is opposite the first directionand in the same plane as the first direction. For example, thetensioning line operates to deflect the distal end of the flexible guidetube in a direction “X” and the second tensioning line operates todeflect the distal end of the flexible tube in a direction “−X,” or inthe opposite direction.

A proximal end of the flexible guide catheter and the two tensioninglines are coupled to a handle that is configured to be gripped by amedical practitioner to steer and insert the flexible guide catheterinto the patient. The practitioner holds the handle while advancing andsteering the guide catheter through the vasculature of the patient. Oncethe guide catheter is advanced to the desired location, the medicalpractitioner advances the treating catheter or treating instrumentthrough the interior of the guide catheter. The handle may have manyforms, but in one aspect, the handle has a medial portion with alongitudinal axis substantially parallel with a distal portion of theflexible guide tube. A first actuator is disposed on a front end of thehandle (i.e., proximal the medial section). A second actuator isdisposed on a back end of the handle (i.e., distal the medial section).The two actuators each operate to generate tensioning force acting onthe first tensioning line and the second tensioning line.Advantageously, the medical practitioner can flex (i.e., deflect orbend) the distal end of the catheter in the same plane of deflectionwith either hand or both hands employing either the first actuator, thesecond actuator, or both actuators at the same time. This enhances thepractitioner's ability to effectively steer the guide catheter in thepatient by optimizing the practitioner's steering options to steer thedistal end of the guide catheter in the same plane of movement. In oneaspect, the first and second actuators are both coupled to a first driveadapted to pull on the first tensioning line and the second driveadapted to pull on the second tensioning line.

While there are numerous manners to access cavities and/or organs of apatient, including femoral arterial, brachial arterial, or jugularaccess, in one aspect, the guide catheter may be advanced through asubxiphoid access point to access the thoracic cavity and the heart inparticular. Generally, an incision may be made below the xiphoid processoverlying the entry site and the linea alba, for instance, may beincised to obtain the subxiphoid access. The guide catheter may beintroduced through the incision and superiorly into the thoracic cavityuntil the distal tip of the guide catheter is adjacent to thepericardial sac of the heart. Once desirably positioned, the working orsurgical theater is assessed and the clinician is free to advance atreating catheter or other treating tool about (i.e., over the guide orthrough an internal lumen) the guide catheter.

FIGS. 1, 2A and 2B show a steerable guide catheter 10 in accordance withone aspect of the present technology. The guide catheter 10 comprises adeflectable guide tube 12 with an internal lumen 16 carried by a handle40 that houses at least a portion of the proximal end of the guide tube12 therein. In the aspect shown in FIG. 1, the handle 40 is adapted tohouse a steering mechanism described in greater detail below. Distal (orfront) actuator 18 and proximal (or back) actuator 19 comprise a dialand internal components that can be rotationally manipulated in opposingdirections as indicated by arrows C and D. The actuators are disposed atopposing ends of the handle 40, either in front of or behind a medialportion 41 of the handle 40. The actuators are coupled to a steeringmechanism such that together the actuators and the steering mechanismcomponents comprise a steering assembly. In one aspect, the steeringmechanism comprises first and second tensioning lines 20 disposed withinthe housing 40 and comprise, for example, a cord, a Kevlar line, acontrol wire, or other line made from metallic or non-metallicmaterials. The tensioning lines 20 are coupled to the guide tube 12 suchthat a tension force (e.g., pulling) acting on the tensioning linesoperates to flex the guide tube 12.

FIG. 2A shows a cross section of the guide tube 12 a when the guide tube12 is within handle 40 in accordance with one aspect. FIG. 2B shows across section of the guide tube 12 b when the guide tube 12 is outsidethe handle 40 in accordance with one aspect of the technology. Aportion, however, can also be within the handle as the guide tube 12transitions form outside the handle 40 to inside the handle 40. Thetensioning lines 20 travel substantially an entire length of the guidetube 12 b to the distal end portion 28 to couple with a steeringmechanism inside the handle 40. More particularly, the tensioning lines20 travel within a secondary lumen 25 a and 25 b (shown on FIG. 2B) oranother dedicated lumen through the guide tube 12 b when outside handle40 and are disposed about an exterior of the guide tube 12 a when insidethe handle 40. That is, tensioning lines 20 transition from outside theguide tube 12 a to inside the guide tube 12 and into secondary lumens 25a, 25 b when the guide tube 12 extends outside the handle 40 through thenose 42 of the handle 40. In one aspect, the guide tube 12 b comprisesan exterior diameter that is greater when outside of handle 40 than whenguide tube 12 a is inside handle 40, while the interior diameter of theguide tube 12 a and 12 b remains the same regardless. In one aspect, theflexible guide tube 12 may be constructed, for example, by extrusionusing standard flexible, medical grade plastic materials or by othermeans and other materials as is known in the art. The guide tube 12,while flexible, may have a plastic memory or bias that normally orientsthe distal end portion 28, sometimes called the distal end region 28, ofthe guide tube 12 in an essentially straight configuration. The steeringmechanism is used to enable greater control of the orientation of thedistal end portion 28 even if a plastic memory or bias is used to resista deflected distal region. For example, in one aspect, once deflected toa desired configuration, actuators 18, 19 can be locked in place tomaintain a particular guide tube 12 geometry.

The handle 40 is sized to be conveniently held by a clinician, and issized to introduce the guide tube 12 b into an interior body region thathas been targeted for treatment. The handle 40 may be constructed, forexample, from molded plastic, though other materials and types ofmanufacturing are contemplated and known to persons of ordinary skill inthe art. In operation, the steering mechanism is actuated by actuators18 and 19 to deflect the distal end portion 28 of guide tube 12 b out ofits essentially straight configuration and into a bent or deflectedconfiguration, as shown in FIG. 1. This is accomplished by thetensioning lines 20 which are coupled to guide tube 12 b at (oradjacent) the distal end portion 28 and are tensioned by the steeringmechanism to provide a force that deflects the distal end portion 28 ofguide tube 12 b. In one aspect, the steering mechanism is adapted tohold the distal end portion 28 of the guide tube 12 b in its deflectedcondition, thereby maintaining a treating tool placed within the guidetube 12 b in its desired relationship during use. The steerable guidetube 12 b obviates the need to equip the treating tool with an on-boardsteering mechanism or a guide wire lumen. Advantageously, the actuators18 and 19 each control the tensioning lines 20. The clinician cantherefore move the distal end portion 28 of guide tube 12 in the sameplane of movement from either the distal or proximal end of the handle40. This optimizes the operator's ability to advance/operate the guidetube 12 with either hand (left or right hand). This is particularlyuseful when advancing a treatment catheter or operating a treatment toolwith one hand while holding and/or operating the guide catheter 10 withthe other hand.

In one aspect of the technology, the proximal end of the guide tube 12 acomprises hemostasis or backflow check seals or valves to prevent bloodloss and retrograde flow of air into the circulatory system. A hub 14 isdisposed on the proximal end of the handle 40 and comprises such ahemostasis seal. The seal comprises an annular soft elastomeric gasketthat seals against catheters, instruments, and the dilator, insertedtherethrough. The seal can further comprise a valve such as a stopcock,one-way valve such as a duckbill or flap valve, or the like to preventsignificant blood loss and air entry when an instrument or catheter isremoved from the lumen 16 of the guide catheter 10. The soft annularseal can further comprise a mechanism to compress the inner diameter ofthe seal radially inward, such as the mechanisms found on Tuohy-Borstvalves. In one aspect, the hub 14 further comprises one or moresideports for injection of contrast media such as Omnipaque, Renografin,or other Barium-loaded solutions, for example, or anticoagulantsolutions such as heparin, coumadin, persantin, or the like, or for themeasurement of pressure at or near the distal end 28 of the guidecatheter 10, though fluids may be injected directly through the valve inthe hub 14. In one aspect, a plurality of hemostasis valves and/or fluidinput connectors or ports or disposed about the hub. In one aspect, thehub 14 comprises a central lumen 15 coupled directly to a Tuohy-Borstvalve 11 integrally formed with the hub 14. The lumen of the hub 14 iscoupled to the lumen 16 of the guide tube 12 or comprises the proximalend of the guide tube 12 itself. In one aspect, a hemostasis adapter isinserted through the Tuohy-Borst valve. The hub 14 comprises a largediameter Tuohy-Borst valve 11, which can have a capacity ranging from 10to 30 French (though other much smaller valves, 5-9 French, for example,may be used). Such large Tuohy-Borst valves may not seal fully onclosure, or it may not seal at all unless it surrounds a tube largerthan 5 or 6 French, for example. The hemostasis adapter can be insertedinto such a Tuohy-Borst valve 11 and the Tuohy-Borst valve 11 tightenedto obtain a seal around the hemostasis adapter tubing, which can rangein diameter from 5 to 10 French. In one aspect, the Tuohy-Borst valve 11can seal around and allow passage of tubing ranging from 6 to 18 Frenchin diameter. The enlargement can pass through the Tuohy-Borst or othervalve but with increased force, which can be relieved once theenlargement can be past the valve. The enlargement also helps preventinadvertent withdrawal of the hemostasis adapter from the hub 14. In oneaspect, a stopcock and purge line can be used for aspiration of blood orsaline or the purging of air from the hub lumen.

In one aspect of the technology, the distal end 28 of the guide tube 12comprises radiopaque markers to denote the beginning and end of thedeflecting regions of the catheter. The guide catheter 10 can compriseradiopaque materials such as gold wire, platinum wire, tantalum wire, orcoatings of the aforementioned over a malleable, stainless steel,deformable reinforcing layer. The radiopaque materials may also comprisehybrid metallic polymer materials. Such radiopaque markings areespecially useful insofar as they allow the operator to more clearlyvisualize the extent to which the guide catheter 10 is properly placedand/or the extent to which the distal end 28 of the guide tube 12 hasbeen deflected by the operator. In one aspect, a radiopaque marker bandis affixed to the distal end 28 of the guide catheter 10 substantiallynear the distal tip 29 so that the position of the distal tip 29 can beobserved and controlled relative to the wall of the left atrium, othercardiac structures, or other portions of the body. This radiopaquemarker band can be a non-expandable, axially elongate tubular structurethat is coupled to the guide tube 12. The radiopaque marker bands canfurther be configured to appear different under fluoroscopy by usingdifferent shapes and/or types of materials for different bands. Yetanother configuration of radiopaque marker bands can be achieved byusing malleable wire windings or nano-sized particles of gold, tantalum,platinum alloys, or the like, which are embedded within the guide tube12.

FIGS. 3-5 disclose components of the steering mechanism in accordancewith one aspect of the technology with portions of the housing removed.Different components of the handle 40 are not shown in order toillustrate aspects of the steering assembly within the handle 40. In oneaspect, the steering assembly comprises first and second actuators 18,19. The actuators each include internal teeth 45 that are adapted tomate with teeth 46 of gear 47. Gear 47 is disposed about opposing sidesof linear drive shaft 49 that is configured for rotation and translationrelative to the actuators. The drive shaft 49 comprises a first set ofspiraled threads 50 with a pitch oriented in a first direction and asecond set of spiraled threads 51 having a pitch oriented in a seconddirection and a shaft hub 52 disposed in the center of the shaft 49 andbetween the first and second set of spiraled threads. A first drive 60(also referred to herein as a drive nut) and second drive 61 aredisposed about opposing sides of the linear drive shaft 49. Each of thefirst and second drive nuts comprise an aperture within the main body 62with internal threads adapted to mate with the threads 50, 51 of theshaft 49. The drive nuts 60, 61 further comprise a tab or wing portion63 extending away from the main body 62 such that wings 63 of therespective drive nuts 60, 61 are on opposing sides of the guide tube 12inside handle 40. The drive nuts 60, 61 are configured to mate withtensioning lines 21 and 22 that also extend longitudinally aboutopposing sides of the guide tube 12 to a distal end 28 of guide tube 12.In one aspect, the tensioning lines 21, 22 are coupled to apertures 65located within with wing 63 of drive nuts 60, 61, however, thetensioning lines may be soldered, bonded, or otherwise coupled to thedrive nuts so long as the linear movement of the nuts translates intolinear movement the tensioning lines 21, 22.

As the first 18 or second 19 actuator is rotated, gear 47 is likewiserotated resulting in rotation of linear drive shaft 49. The rotationalmovement of the linear drive shaft 49 translates into linear movement ofthe drive nuts 60, 61 about drive shaft 49. In one aspect, therespective pitches of the first and second spiraled threads 50, 51 aresubstantially the same even though they are oriented in differentdirections. That is, as the drive shaft 49 is rotated, drive nuts 60, 61will travel the same linear distance about the shaft 49. However,because the direction of the pitch of the first and second threads areoriented in opposite directions (i.e., one is a left-handed thread whilethe other is a right-handed thread) the direction of the linear travelof the respective drive nuts will be in opposite, but paralleldirections as shown by arrows A and B. Consequently, a tensioning forcewill act upon tensioning lines 21, 21 respectively depending on thedirection of rotation of actuators 18 and 19. When rotated in directionC, for example, drive nut 60 may move in the direction B (i.e., towardsthe proximal end of the handle 40) resulting in a tensioning forceacting on tensioning line 21. At the same time, drive nut 61 is moved indirection A (i.e., away from the proximal end of the handle 40) provideslack in the tensioning line 22. Likewise, when the actuators 18 and 19are rotated in direction D, drive nut 61 is moved in direction B anddrive nut 60 is moved in direction A.

In accordance with one aspect of the technology, a second drive shaft isenclosed within the cavity of handle 40 and coupled to a second set ofactuators. The second drive shaft is coupled to third and fourth drivenuts that operate to create a tensioning force in the third and fourthtensioning lines. In one aspect, the third and fourth drive nuts areoff-set from the first and second drive nuts 60, 61 about thecircumference of the guide tube 12 by 90 degrees. In this manner, thirdand fourth tensioning lines that extend longitudinally about the lengthof the guide tube 12 through secondary lumens 26 a and 26 b and areoperated by movement of the third and fourth drive nuts and function toflex the distal end 28 of the guide tube 12 b in a Y and −Y direction.In other words, while the first and second tensioning lines flex thedistal 28 of guide tube 12 in a single plane of movement (i.e., animaginary X and −X direction), the third and fourth tensioning linesfunction to flex the distal end 28 of the guide tube 12 in an additionalplane of movement (i.e., an imaginary Y and −Y direction). While a 90degree off-set has been referenced herein, it is understood that thethird and fourth tensioning lines can be oriented to deflect the distalend 28 of the guide tube 12 in any other plane off-set from the plane ofoperation associated with the first and second tensioning lines. Forexample, in one aspect of the technology, the third and fourthtensioning lines are off-set from the plane of operation associated withthe first and second tensioning lines by 15 degrees, 30 degrees, 45degrees, or 60 degrees. The tensioning lines may also be off-set atother orientations that lie between 1 and 89 degrees as suits aparticular application.

In another aspect of the technology, the third and fourth tensioninglines are directed through secondary lumens 27 a and 27 b. Secondarylumens 27 a and 27 b (which may also be called tertiary lumens orquaternary lumens) are disposed adjacent lumens 25 a and 25 b butterminate at a pre-determined distance away from the tip 29 of thedistal end 28 of guide tube 12. In this manner, the third and fourthtensioning lines operate to flex the guide tube in substantially thesame direction (and hence the same operating plane) as the first andsecond tensioning lines 50, 51. However, because the lumens 27 a and 27b (and consequently the third and fourth tensioning lines) terminate adistance away from the distal end 28, the flexing action occurs agreater distance away from the distal tip 29 than the flexing thatresults from operation of the first and second tensioning lines. It isunderstood that numerous tensioning lines can be used in the samesecondary lumen (25 a, 25 b, 26 a, 26 b, 27 a, and 27 b) if desired, asingle tensioning line can be used in each secondary lumen, or a one ormore pairs of tensioning lines may be used in one or more secondarylumens.

In accordance with one aspect of the technology, similar to the firstlinear drive shaft 49, the second drive shaft comprises threads orientedin opposing directions. Likewise, the opposing threads have a similarpitch so that the distance of linear travel of the associated drive nutsis equivalent even though the direction of the travel is in oppositedirections. However, in one aspect, the threads of the second lineardrive shaft have a pitch that is more shallow (i.e., having a lighter orless angled pitch) than the pitch of the threads on the first lineardrive shaft. A lighter or shallower pitch results in smaller lineartravel with the same amount of rotation of the drive shaft. In thismanner, the clinician can place the distal end 28 of the guide tube 12in a “rough” location by using the first set of actuators 18, 19 and thefirst linear drive shaft 49 and switch to the second set of actuatorsand the second drive shaft to flex the distal end 28 of guide tube atsmaller intervals for more precise movements. In this aspect of thetechnology, the third and fourth tensioning lines can terminate at thesame longitudinal location as the first and second tensioning lines.

Reference has been made herein to aspects of the technology where thirdand fourth actuators operate a second linear drive shaft. However, inone aspect of the technology, first 18 and second 19 actuators areconfigured to operate the first linear drive shaft 49 and the secondlinear drive shaft. As shown in FIGS. 3-5, the actuators 18 and 19comprise a plurality of internal teeth that mate with the teeth 46 ofgear 47 of drive shaft 49. When either actuator 18 or 19 is rotated, thedrive shaft 49 is also rotated. In one aspect of the technology, thesecond drive shaft also comprises a gear with teeth configured to matewith actuator 18 and 19. However, the gears of the second drive shaftare longitudinally off-set from the actuators 18 and 19. That is, in oneaspect, the gears associated with the second drive shaft are slightlycloser to the center of the second drive shaft than the gears 47 locatedon the first drive shaft. The actuators 18 and 19 are disposed about thehandle such that they are longitudinally biased to engage gear 47 ofdrive shaft 49. However, the actuators may slide on the handlelongitudinally inward towards the medial portion 41 of the handle 40thereby engaging the gears of the second drive shaft. In this manner,the same set of actuators may be used to drive a plurality of differenttensioning lines, whether the different (e.g., the third and fourth)tensioning lines operate in the same plane as the first and secondtensioning lines, or in a different plane (e.g., the Y and −Y plane,etc.).

Reference has been made herein to a pulling force on tensioning lines.However, it is understood that a number of different mechanisms may beemployed to create tension in the tensioning lines without departingfrom the scope of the disclosed technology. For example, the tensioninglines may comprise a shape memory alloy (e.g., Nitinol) that is biasedin a straight or linear configuration but when subjected to anelectrical signal or charge, will flex into a pre-determinedconfiguration. In this aspect, an actuator disposed on a proximal end ofthe handle 40 would function to flex the distal end 28 of guide tube 12in both the X and −X directions. Likewise, a second actuator disposed ona distal end of the handle 40 would operate the same tensioning linesassociated with the proximal actuator and function to flex the distalend 28 of guide tube 12 in both the X and −X directions.

Certain aspects of the technology include methods of flexing a distalend 28 of a guide tube wherein a clinician displaces either (or both) afirst or second actuator 18, 19 disposed about a handle 40 of thesteerable guide catheter 10. The steerable guide catheter 10 comprises aflexible guide tube 12 having a deflectable distal end 28 and a proximalend housed within a cavity of a handle 40. First and second drive nuts60, 61 are disposed about a linear drive shaft 49 within the handle 40,the first drive nut 60 being coupled to a first tensioning line 21 andthe second drive nut 61 being coupled to a second tensioning line 22.The first and second tensioning lines are disposed on opposing sides ofthe flexible guide tube 12 and extend longitudinally along the guidetube 12 to its distal end 28. The method further comprises displacingthe first drive nut 60 in a first direction while simultaneouslydisplacing the second drive nut 61 in a second direction, wherein thefirst direction is opposite and parallel the second direction. In oneaspect of the technology, the linear distance of displacement of thefirst drive nut 60 is substantially equivalent to the lineardisplacement of the second drive nut 61. The method further comprisesdisplacing the first tensioning line 21 when the first drive nut 60 isdisplaced in the first direction and displacing the second tensioningline 22 in the first direction when the second drive nut 62 is displacedin the first direction thereby deflecting a distal end of the flexibleguide tube 12. In one aspect, the first and second drive nuts 60, 61 areboth displaced linearly about the linear drive shaft 49 by displacingeither the first 18 or second actuator 19.

It is noted that no specific order is required in these methods unlessrequired by the claims set forth herein, though generally in someembodiments, the method steps can be carried out sequentially.

Of course, it is to be understood that the above-described arrangementsare only illustrative of the application of the principles of thepresent invention. Numerous modifications and alternative arrangementsmay be devised by those skilled in the art without departing from thespirit and scope of the present invention and the appended claims areintended to cover such modifications and arrangements. Thus, while thepresent invention has been described above with particularity and detailin connection with what is presently deemed to be the most practical andpreferred embodiments of the invention, it will be apparent to those ofordinary skill in the art that numerous modifications, including, butnot limited to, variations in size, materials, shape, form, function andmanner of operation, assembly and use may be made without departing fromthe principles and concepts set forth herein.

What is claimed is:
 1. A steerable guide catheter comprising: a flexibleguide tube having a deflectable distal end; at least first and secondtensioning lines coupled to the deflectable distal end of the flexibleguide tube, the first tensioning line being configured to deflect thedistal end of the flexible guide tube in a first direction and thesecond tensioning line being configured to deflect the distal end of theflexible guide tube in a second direction that is opposite the firstdirection; and a handle having a distal end coupled to the flexibleguide tube, said handle comprising: a medial portion having alongitudinal axis substantially parallel with at least a portion of theflexible guide tube; a first actuator disposed at a first end of thehandle; and a second actuator disposed at a second end of the handleopposite the first end, wherein the first actuator operates to generatea tensioning force acting on the first tensioning line and the secondtensioning line and the second actuator operates to generate atensioning force acting on the first tensioning line and the secondtensioning line, wherein the first and second actuators are each coupledto a rotatable gear, said rotatable gear being coupled to a linear driveshaft disposed within an interior cavity of the handle, wherein thefirst and second actuators are both coupled to a first drive adapted topull on the first tensioning line and a second drive adapted to pull onthe second tensioning line, and wherein the first drive and the seconddrive are disposed about the linear drive shaft, and wherein the firstdrive and the second drive each comprise a drive nut having athrough-aperture with a plurality of threads disposed therein, thethreads of the drive nuts being configured to mate with threads disposedabout an exterior of the linear drive shaft.
 2. The steerable guidecatheter of claim 1, wherein the first and second tensioning linesextend longitudinally at opposing sides of the flexible guide tube andinto the interior cavity of the handle.
 3. The steerable guide catheterof claim 1, wherein the threads disposed about the exterior of thelinear drive shaft comprise a plurality located on a distal portion ofthe linear drive shaft and oriented in a first direction and a pluralitylocated on a proximal portion of the linear drive shaft and oriented ina second direction, wherein the first direction of the plurality ofthreads of the distal portion is opposite the second direction of theplurality of threads of the proximal portion.
 4. The steerable guidecatheter of claim 1, wherein each drive nut has a tension line couplingdisposed about a wing of the drive nut.
 5. The steerable guide catheterof claim 1, wherein the through-aperture of the drive nut of the firstdrive is coupled to the linear drive shaft, the through-aperture of thedrive nut of the second drive is coupled to the linear drive shaft, asecond aperture of the drive nut of the first drive is coupled to thefirst tensioning line, and a second aperture of the drive nut of thesecond drive is coupled to the second tensioning line.
 6. A steerableguide catheter comprising: a flexible guide tube having a deflectabledistal end; at least two tensioning lines coupled to the deflectabledistal end of the flexible guide tube, wherein a first tensioning lineof the at least two tensioning lines is configured to deflect the distalend of the flexible guide tube in a first direction and a secondtensioning line of the at least two tensioning lines is configured todeflect the distal end of the flexible guide tube in a second direction;and a handle coupled to the flexible guide tube, the handle comprising:a first actuator and a second actuator each coupled to a rotatable gearthat is coupled to a drive shaft, the drive shaft having thereon a firstdrive nut and a second drive nut, the first drive nut being coupled tothe first tensioning line and the second drive nut being coupled to thesecond tensioning line, wherein both the first actuator and the secondactuator are configured to rotate the gear to move both the first andsecond drive nuts in opposite directions.
 7. The steerable guidecatheter of claim 6, wherein the first actuator is disposed about adistal end of the handle and the second actuator is disposed about aproximal end of the handle.
 8. The steerable guide catheter of claim 6,wherein a proximal end of the flexible guide tube extends through thehandle.
 9. The steerable guide catheter of claim 6, further comprising acompression fitting disposed about a proximal end of the handle andenclosing a proximal end of the flexible guide tube.
 10. The steerableguide catheter of claim 6, further comprising third and fourth actuatorsdisposed about the handle, wherein the at least two tensioning linescomprise third and fourth tensioning lines, and wherein the third andfourth actuators are coupled to a second drive shaft located within thehandle and are configured to operate the third and fourth tensioninglines, said third and fourth tensioning lines being configured todeflect the distal end of the flexible guide tube in third and fourthdirections, respectively.
 11. The steerable guide catheter of claim 6,wherein the first and second tensioning lines are longitudinallydisposed at opposing sides of the flexible guide tube.
 12. The steerableguide catheter of claim 6, wherein the first drive nut comprises aplurality of threads configured to mate with a first plurality ofthreads on a first end of the drive shaft and the second drive nutcomprises a plurality of threads configured to mate with a secondplurality of threads on a second end of the drive shaft.
 13. Thesteerable guide catheter of claim 12, wherein the first plurality ofthreads on the first end of the drive shaft are oriented in a firstdirection and the second plurality of threads on the second end of thedrive shaft are oriented in a second direction, the first directionbeing opposite the second direction.
 14. The steerable guide catheter ofclaim 13, wherein a pitch of the first plurality of threads isequivalent to a pitch of the second plurality of threads.
 15. Thesteerable guide catheter of claim 6, wherein each of the first andsecond drive nuts comprise a first end having a first thickness taperingto a second end having a second thickness smaller than the firstthickness.
 16. The steerable guide catheter of claim 15, wherein thesecond end of the first drive nut and the second end of the second drivenut are disposed about opposing sides of the flexible guide tube.
 17. Asteerable guide catheter comprising: a flexible guide tube having adeflectable distal end; two tensioning lines coupled to the deflectabledistal end of the flexible guide tube extending down a longitudinallength of the flexible guide tube, wherein the tensioning lines areconfigured to deflect the distal end of the flexible guide tube; and ahandle coupled to the flexible guide tube, the handle comprising: arotatable gear coupled to a linear drive shaft; first and secondrotational actuators coupled to the rotatable gear, each rotationalactuator configured to induce rotation of the rotatable gear and thelinear drive shaft when rotated; a first drive nut coupled to the lineardrive shaft and a first tensioning line of the two tensioning lines; anda second drive nut coupled to the linear drive shaft and a secondtensioning line of the two tensioning lines, wherein, when the first orsecond rotational actuators are rotated, the first drive nut is linearlydisplaced about the drive shaft in a first direction and the seconddrive nut is linearly displaced about the drive shaft in a seconddirection that is opposite the first direction.
 18. The steerable guidecatheter of claim 17, wherein the first direction and the seconddirection are substantially parallel to one another.
 19. The steerableguide catheter of claim 17, wherein the linear displacement of the firstdrive nut is substantially equivalent to the linear displacement of thesecond drive nut.
 20. The steerable guide catheter of claim 17, furthercomprising a valve disposed within a proximal end of the flexible guidetube.
 21. A steerable guide catheter comprising: a flexible guide tubehaving a deflectable distal end; at least first and second tensioninglines coupled to the deflectable distal end of the flexible guide tube,the first tensioning line being configured to deflect the distal end ofthe flexible guide tube in a first direction and the second tensioningline being configured to deflect the distal end of the flexible guidetube in a second direction that is opposite the first direction; and ahandle having a distal end coupled to the flexible guide tube, saidhandle comprising: a medial portion having a longitudinal axissubstantially parallel with at least a portion of the flexible guidetube; a first actuator disposed at a first end of the handle; and asecond actuator disposed at a second end of the handle opposite thefirst end, wherein the first actuator operates to generate a tensioningforce acting on the first tensioning line and the second tensioning lineand the second actuator operates to generate a tensioning force actingon the first tensioning line and the second tensioning line, wherein thefirst and second actuators are each coupled to a rotatable gear, saidrotatable gear being coupled to a linear drive shaft disposed within aninterior cavity of the handle, and wherein a distal portion of thelinear drive shaft comprises a plurality of threads disposed about anexterior of the linear drive shaft oriented in a first direction and aproximal portion of the linear drive shaft comprises a plurality ofthreads disposed about the exterior of the linear drive shaft orientedin a second direction, wherein the first direction of the plurality ofthreads of the distal portion is opposite the second direction of theplurality of threads of the proximal portion.
 22. The steerable guidecatheter of claim 21, wherein the first and second actuators are bothcoupled to a first drive adapted to pull on the first tensioning lineand a second drive adapted to pull on the second tensioning line. 23.The steerable guide catheter of claim 22, wherein the first and seconddrives each comprise a drive nut, each drive nut having a tension linecoupling disposed about a wing of the drive nut.
 24. The steerable guidecatheter of claim 21, wherein the first and second tensioning linesextend longitudinally at opposing sides of the flexible guide tube andinto the interior cavity of the handle.
 25. The steerable guide catheterof claim 24, wherein the first and second actuators are both coupled toa first drive adapted to pull on the first tensioning line and a seconddrive adapted to pull on the second tensioning line, and wherein thefirst drive and the second drive are disposed about the linear driveshaft.
 26. The steerable guide catheter of claim 25, wherein the firstdrive and the second drive each comprise a drive nut having athrough-aperture with a plurality of threads disposed therein, thethreads of the first drive nut being configured to mate with theplurality of threads of the distal portion of the linear drive shaft andthe threads of the second drive nut being configured to mate with theplurality of threads of the proximal portion of the linear drive shaft.27. The steerable guide catheter of claim 26, wherein thethrough-aperture of the drive nut of the first drive is coupled to thelinear drive shaft, the through-aperture of the drive nut of the seconddrive is coupled to the linear drive shaft, a second aperture of thedrive nut of the first drive is coupled to the first tensioning line,and a second aperture of the drive nut of the second drive is coupled tothe second tensioning line.
 28. A steerable guide catheter comprising: aflexible guide tube having a deflectable distal end; at least first andsecond tensioning lines coupled to the deflectable distal end of theflexible guide tube, the first tensioning line being configured todeflect the distal end of the flexible guide tube in a first directionand the second tensioning line being configured to deflect the distalend of the flexible guide tube in a second direction that is oppositethe first direction; and a handle having a distal end coupled to theflexible guide tube, said handle comprising: a medial portion having alongitudinal axis substantially parallel with at least a portion of theflexible guide tube; a first actuator disposed at a first end of thehandle; and a second actuator disposed at a second end of the handleopposite the first end, wherein the first actuator operates to generatea tensioning force acting on the first tensioning line and the secondtensioning line and the second actuator operates to generate atensioning force acting on the first tensioning line and the secondtensioning line, wherein the first and second actuators are each coupledto a rotatable gear, said rotatable gear being coupled to a linear driveshaft, wherein the linear drive shaft is coupled to a first driveadapted to pull on the first tensioning line and a second drive adaptedto pull on the second tensioning line, and wherein the first and seconddrives each comprise a drive nut, each drive nut having a tension linecoupling disposed about a wing of the drive nut.
 29. The steerable guidecatheter of claim 28, wherein the first and second tensioning linesextend longitudinally at opposing sides of the flexible guide tube andinto an interior cavity of the handle.
 30. The steerable guide catheterof claim 28, wherein the linear drive shaft is disposed within aninterior cavity of the handle.
 31. The steerable guide catheter of claim28, wherein a distal portion of the linear drive shaft comprises aplurality of threads disposed about an exterior of the linear driveshaft oriented in a first direction and a proximal portion of the lineardrive shaft comprises a plurality of threads disposed about the exteriorof the linear drive shaft oriented in a second direction, wherein thefirst direction of the plurality of threads of the distal portion isopposite the second direction of the plurality of threads of theproximal portion.
 32. The steerable guide catheter of claim 28, whereinthe first drive and the second drive are disposed about the linear driveshaft.
 33. The steerable guide catheter of claim 32, wherein each drivenut has a through-aperture with a plurality of threads disposed therein,the threads of the drive nuts being configured to mate with threadsdisposed about an exterior of the linear drive shaft.
 34. The steerableguide catheter of claim 33, wherein the through-aperture of the drivenut of the first drive is coupled to the linear drive shaft, thethrough-aperture of the drive nut of the second drive is coupled to thelinear drive shaft, a second aperture of the drive nut of the firstdrive is coupled to the first tensioning line, and a second aperture ofthe drive nut of the second drive is coupled to the second tensioningline.
 35. A steerable guide catheter comprising: a flexible guide tubehaving a deflectable distal end; at least two tensioning lines coupledto the deflectable distal end of the flexible guide tube, wherein afirst tensioning line of the at least two tensioning lines is configuredto deflect the distal end of the flexible guide tube in a firstdirection and a second tensioning line of the at least two tensioninglines is configured to deflect the distal end of the flexible guide tubein a second direction; a handle coupled to the flexible guide tube, thehandle comprising: a first actuator and a second actuator each coupledto a drive shaft, the drive shaft having thereon a first drive nut and asecond drive nut, the first drive nut being coupled to the firsttensioning line and the second drive nut being coupled to the secondtensioning line, wherein both the first actuator and the second actuatorare configured to move both the first and second drive nuts in oppositedirections; and third and fourth actuators disposed about the handle,wherein the at least two tensioning lines comprise third and fourthtensioning lines, and wherein the third and fourth actuators are coupledto a second drive shaft located within the handle and are configured tooperate the third and fourth tensioning lines, said third and fourthtensioning lines being configured to deflect the distal end of theflexible guide tube in third and fourth directions, respectively.